Chromosome Numbers, Fertility and Rhizome Expression of Hybrids Between Grain Sorghum and Johnsongrass1

Synopsis Hybrids between either male‐fertile or genetic male‐sterile grain sorghum and Johnsongrass included highly sterile 30‐chromosome and relatively fertile 40‐chromosome types. Hybrids between cytoplasmic male‐sterile gram sorghum and Johnsongrass included highly sterile 30‐chromosome and male‐sterile 40‐chromosome types. Rhizomes of the 30‐chromosome types were vigorous; those of the 40‐chromosome types were generally much weaker.